1. Field of the Invention
The device and method of this invention reside in the area of hand grips for firearms and more particularly relate to an improved anatomical hand grip for a firearm for the positioning of the mid-portion of the distal phalanx of the index finger directly on the trigger for improved accuracy when firing the firearm and to the method of determining the appropriate size of the hand grip.
2. History of the Prior Art
Hand grips for firearms, such as handguns and long rifles, are well known in the prior art. Such hand grips are often ergonomically formed of materials which are easy to grip, some of which are even compressible, to allow the user to better grasp the firearm handle. Handguns are well known for such grips which often are provided in multiple pieces which pieces are attached to the sides of the handle. Such grips are also utilized on rifles and other types of firearms.
U.S. Pat. No. 6,112,446 to Forster et al discusses the provision of grip panels in different widths and thicknesses to accommodate the different sized-hands of different users. Forster fails to perceive any relationship between the grip size and the importance of centrally positioning the mid-portion of the distal phalanx of the trigger finger on the trigger which positioning is so important for precision aiming of the firearm.
When firing firearms mounted with hand grips of the prior art, care must be taken to balance the force exerted by the user""s hand in gripping the handle of the firearm and the pressure on the trigger at the moment of xe2x80x9ctrigger break.xe2x80x9d Trigger break occurs immediately before the actual firing of the gun when the trigger loses almost all mechanical resistance to the pulling action of the trigger finger which movement of the trigger finger is not necessarily on the axis of the holding hand. Since the other fingers are still exerting their previous gripping forces, the result is momentary force imbalance with its corresponding turning torque and movement of the firearm. This imbalance of forces can be minimized and corrected by an experienced shooter in his or her aiming, but only if it is reproducible from shot to shot.
It is an object of this invention to limit the element of force variability caused by the positioning and movement of the trigger finger at the moment of trigger break and thus to improve precision aiming of the firearm. To accomplish this goal the invention herein provides an improved anatomical firearm grip panel having a trigger finger support protrusion for support of the trigger finger to assure its automatic and reproducible placement of the mid-portion of the distal phalanx of the index finger in its optimal position directly in front of the trigger. The device of this invention can be utilized on handguns, semiautomatic handguns, revolvers, rifles, and any other firearm that utilizes a hand grip adjacent to the trigger mechanism. It should be noted that although a semiautomatic pistol is illustrated and discussed herein, the device of this invention can be utilized on any of the aforementioned types of firearms. Further, although the illustrations depict the invention utilized by a right-handed user, it should be noted that the device can be produced and utilized on the opposite side of the handgun for use by left-handed users. Thus the device of this invention should be considered to include a grip panel that not only can be constructed for right-handed users but also can be constructed for left-handed users as well. In addition, although the device of this invention is discussed and illustrated in a most typical configuration of having two separate side grip panels affixed to a firearm handle, it should also be considered as including one-piece wrap-around grips as well as gun handles with grip geometry integrally molded in them.
In firing a firearm, the precise placement of the mid-portion of the distal phalanx of the trigger finger/index finger on the firearm trigger is critical to accurate shooting. Existing firearm grip designs do not provide positioning support of the trigger finger. While such prior art grips are frequently standardized and found comfortable by users, they allow the user too much latitude in positioning the trigger finger, ranging from placing the very tip of the trigger finger on the trigger to placing the base of the distal portion of the index finger on the trigger, both of which placements are undesirable for accurate shooting of the firearm. The placement of the trigger as close as possible to the axis of the holding hand is most desirable to minimize turning torque with regard to the axis of the holding hand upon the firing of the gun. Further, minimizing the mechanical resistance provided by the trigger of the firearm will also reduce such turning torque. Trigger pulls of normal military or law enforcement firearms are in the range of 3-7 lb. Hair triggers have pulls within the range of 0.5-2 oz and are very specialized in their applications. Their usage is limited by safety considerations and often by sporting rules.
The device of this invention extends the support of the trigger finger on the hand grip to a point somewhat beyond the second finger joint to aid in the elimination of what can be referred to as xe2x80x9ctrigger finger play.xe2x80x9d When using on a handgun the hand grip of this invention on a hand gun that has been specially selected for that user, the user tightly grasps the handgun and automatically the mid-portion of the distal phalanx of his trigger finger is positioned directly at the correct point in front of the trigger. Since human hands come in a variety of different sizes with varying finger lengths, the size of the trigger finger support protrusion of the hand grip of this invention required to position a user""s fingers properly on a standard firearm frame will differ depending upon the length of the user""s palm and index finger. To determine the proper size of the trigger finger support protrusion, a method is disclosed herein for the determination of the parameters so that a user can be personally measured for the selection and installation of the correct sized grip to create a firearm for that user which will correctly position the mid-portion of the distal phalanx of the trigger finger of that user directly in front of the trigger.
In target shooting, the technique is to exert a gripping force on the firearm as close as possible to the axis of the holding hand. The main gripping force is exerted by the middle finger and thumb of the shooting hand with the middle finger contracting and pulling the firearm toward the palm of the hand and the thumb providing the side support. This positioning of the middle finger and thumb allows the index finger or trigger finger to be steadily pulled rearwards on the trigger. Once the trigger finger is positioned correctly on the trigger by the device of this invention, not only can the pulling of the trigger be reproducible with a force-balanced grip, but also the user""s firing accuracy can be improved when combined with other techniques, such as breath and other body movement controls.
The use of the device of this invention helps create a grip which provides for very reproducible results since it optimizes and standardizes the position of the trigger finger against the trigger and reduces the ability of the user to position the trigger finger incorrectly.
A further consideration of this invention is that variations in grip thickness are important relative to the contact areas of the thumb and fingers and palm around the grip of the handgun. A typical thumb area contact around the side of the gun is either a thumb rest which is an open-ended small shelf on the upper left side of the grip or an open area on the left grip panel of the gun where the thumb can easily accommodate extending along the upper part of the left grip panel. The other fingers also have an area where they can securely grip the handle of the gun, such as the contact area for the middle finger which includes its proximal phalanx against the right grip panel, the middle phalanx against the front of the handle, and front of the distal phalanx against the left panel. Middle fingers of various lengths can easily accommodate a grip by wrapping around the grip with slightly different joint angles. Thus the grip for the middle finger and other fingers can be much narrower in configuration than the trigger finger support protrusion of this invention, allowing the grip to be much narrower below the trigger finger support protrusion, as described below, which trigger finger support protrusion positions the mid-portion of the distal phalanx of the index finger in the desired position in front of the trigger. With the exception of the trigger finger which moves, the other fingers wrap around the handle of the gun with no difficulty in achieving a reproducible grip; and although molded finger grooves formed within a grip are common in grips, such feature is not absolutely necessary since the middle, ring and little fingers are merely used to grasp the lower narrower portion of the grip and do not affect the proper placement of the trigger finger against the trigger. Further, the trigger finger support protrusion can be provided separately from the lower grip portion or can even be applied onto an existing grip.
It is yet a further object of this invention to provide an improved firearm grip that can be utilized in a multitude of construction methods such as, for example, formed of separate attachable side panels to a standard handgun frame, or formed as part of integral or unitary grips which can be molded from plastic. It should be noted that the structure of the grip of this invention can be incorporated into many different grip forms that are in popular use but which do not benefit from the present invention and method of determining the size of the trigger finger support protrusion of this invention.
It should be noted that in order to determine the parameters of the trigger finger support protrusion of the hand grip of this invention a tape can be attached at one end to the rear of a handgun frame without any grips thereon. The tape has a plurality of measurement indicia thereon, as described further below, against which one can position one""s hand with the thumb hooked around the grip in its normal position. One can then measure the length where the mid-portion of the distal phalanx of the trigger finger is located on the tape, as seen in FIG. 3, and that length measurement can be used to determine the size of the trigger finger support protrusion that would be selected and mounted on the handgun frame from a series of grips, which series can be part of a kit containing many different sizes for the purpose of selecting the correct size for each user of a handgun. It is critically important to determine the profile geometry of the trigger finger support protrusion for a particular brand of handgun frame and using the methodology of this invention appropriate grips for handgun frames of different brands to make the invention universally acceptable for utilization on a variety of firearm handles.